The electrical and optical improvements of AlGaInP micro-light-emitting diodes (µLEDs)
using atomic-layer deposition (ALD) sidewall passivation were demonstrated. Due to the
high surface recombination velocity and minority carrier diffusion length of the AlGaInP
material system, devices without sidewall passivation suffered from high leakage and severe
drop in external quantum efficiency (EQE). By employing ALD sidewall treatments, the 20×
20 µm^ 2 µLEDs resulted in greater light output power, size-independent leakage current …

The efficiency of AlGaInP micro light-emitting diodes (micro-LEDs) was far weaker than that
of GaN-based micro-LEDs in structure and performance. Consequently, there was an urgent
demand to enhance their efficiency. In this study, a citric acid treatment strategy is proposed
to improve the efficiency of red micro-LEDs, and the etching uniformity of different
concentrations was first confirmed. We optimized the concentration of citric acid to 1: 1 and
modulated the wet etching time at 0, 30, 60, 90, and 120 s to treat the sidewalls of devices …